Electron diffraction data are used to investigate the crystal structures of membrane phospholipids and a pore-forming integral membrane protein from E. coli. Lipid microcrystals are easily obtained by growth from solvent, and the electron diffraction data from them can be used to determine acyl chain packing, but not the total crystal structure. The diffraction coherence restriction imposed by elastic bends of such crystals is removed when the materials are epitaxially grown, giving diffraction data in a view normal to the long chain axes and coherently representing the total unit cell contents. Recently acquired high resolution data from a phosphatidylethanolamine will be used to extend the structure analysis begun with a lower resolution data set using rigid body crystallographic refinement with a model based as on a homolog structure determined from X-ray data. Further structure analyses will be done on unstudied phospholipid classes (e.g. phosphatidic acids and phosphatidyl serines) for which electron diffraction data have been obtained. This work will include examination of conformationally fixed, analogs based on configurational isomers of cyclopentane-1,2,3-triol (cyclitol) which are used to probe headgroup geometry in relation to lipid function and represent a greater data base than achieved by single crystal X-ray diffraction. An already begun structure analysis on the E. coli matrix porin will continue by high resolution electron microscopy and electron diffraction to provide a reconstructed three dimensional image of this molecule. Present work on negatively-stained material at 20 angstroms resolution will be extended by low dose techniques on suitably stabilized samples to attempt higher resolution structure elucidation. Eventually other lipids, including cyclitol analogs, can be used to reconstitute the matrix proin two dimensional sheets to probe possible molecular geometrical alterations due to interactions with particular lipid classes. These studies are directly related to functional analyses on this pore-forming system in order to appreciate the structural basis of their phenomenological properties. Directly these studies investigate the geometry of pores used to regulate membrane transport of molecules less than MW 600 but knowledge of such structure may also give some insight into the mechanism of smaller ion selective pores.